In a prior ferroelectric memory (FRAM), a ferroelectric capacitor is used as a smoothing capacitor for a power supply circuit of a semiconductor device. Since the smoothing capacitor is formed at the same time when a capacitor (cell capacitor) of each memory cell in the ferroelectric memory device is formed, it is not necessary to add a new process of forming the smoothing capacitor. Further, since ferroelectric material is used for the capacitor dielectric film, an electrostatic capacitance can be made larger than using general insulating material.